staging: lustre: Fix sparse warnings for undeclared symbols

This patch fixes the sparse warnings in drivers/staging/lustre/lustre/ptlrpc/sec_lproc.c:
sec_lproc.c:58:6: warning: symbol 'sec_flags2str' was not declared. Should it be static?

Signed-off-by: Scott Weir <sjw0410@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>